Spacecraft, such as those used for earth orbit and interplanetary space missions, must be designed within the limits of a number of constraints. Two important constraints are the weight and size of components used in the spacecraft. In addition to such constraints, spacecraft must be designed to perform specified functions within specified parameters. Among these are power load switching and power protection functions of various electrical and electronic subsystems of the spacecraft. Finally, reliability is always an overriding concern in the design of spacecraft.
Traditionally, load switching and protection functions were implemented with relays and fuses. These devices tend to be relatively large and heavy. They are capable of performing only the most basic of power load switching and protection functions. Relays provide only on-off switching and fuses provide only one-time protection, which is not resettable. The reliability of these devices is adequate, but improved reliability is always desirable.
A need arises for a power switching and protection device that provides reduced size and weight, improved functionality, and improved reliability over traditional devices.